/*
  将下面异步代码使用 Promise 的方法改进
  尽量用看上去像同步代码的方式
  setTimeout(function () {
    var a = 'hello'
    setTimeout(function () {
      var b = 'lagou'
      setTimeout(function () {
        var c = 'I ♥ U'
        console.log(a + b +c)
      }, 10)
    }, 10)
  }, 10)
*/

const resolveInSetTimeout = (str, timer = 1000) => {
  return new Promise((resolve, reject) => {
    try {
      setTimeout(resolve, timer, str)
    } catch (error) {
      reject(error)
    }
  })
}

resolveInSetTimeout('hello')
  .then(x => resolveInSetTimeout(`${x}lagou`))
  .then(x => resolveInSetTimeout(`${x}I ♥ U`))
  .then(console.log)
  .catch(console.log)
  



